Ministers are looking at ways of smoothing passenger flows and tackling the worst overcrowding on the busiest services.

Other changes could see libraries, post offices and supermarkets selling train tickets as hundreds of ticket offices are closed.

According to Department for Transport officials this could see ticket selling machines being installed at outlets across the country, where staff would also be given special training in servicing rail passengers.

The proposals, unveiled by Justine Greening, the Transport Secretary, follow the publication of a report into the rail industry by Sir Roy McNulty.

She told MPs that the long term aim of the Government was to end inflation busting rail fares by cutting the cost of running the rail industry by £3.5 billion a year.

A Government consultation document, setting out the overhaul in how train tickets are sold, says the current system in which all fares are the same within the morning and even peak could be changed.

"Failing to optimise use of the capacity in these instances could mean placing more strain and more costs on the network during peak periods than is really necessary," it warned.

"If commuter demand could be "smoothed" even within the 7-10 am and 4-7pm windows, this would enable capacity to be used more effectively and could allow more people to travel overall."

According to the DfT's calculations, the commuting peak in London, Birmingham and Leeds takes place between 8.30 and 9am.

Other changes could see rises for fares just outside the official rush hours, while those just inside would be reduced.

Ministers are also looking at using smart ticketing to ease demand. This would see commuters outside London being able to use a system similar to the Oyster card in London.

This would see commuters, whose season tickets charge them for daily travel irrespective of whether they make the journey, no longer being expected to pay when they stay at home or travel outside the rush hour.

RMT General Secretary Bob Crow gave the proposals a hostile reception. "This Government rail plan isn't a recipe for efficiency, it's a recipe for exploitation with the train operators given the green light to rob passengers blind to travel on overcrowded and unsafe trains in the name of private profit," he said.

"Axing ticket offices and guards will turn stations and trains into a criminals paradise. For passengers it will mean the double scandal of being mugged by those who set the fares and then running the risk of being mugged by yobbos using the destaffed services as a cover for violence and assaults."

But the proposals were given a guarded welcome by Anthony Smith, chief executive of Passenger Focus, the consumer watchdog.

"Rail passengers will welcome the Government's desire to stop the seemingly endless rounds of above-inflation fare rises, as well as acknowledge that radical reform of the fares and ticketing system is need," he said.

"No-one could disagree with the need for a more efficient and cost-effective railway, but what matters to passengers is how all this reform actually pans out in practice. How will it affect the way we travel?

"Changes to the way the railway is run and fares system need to pass two tests: will passengers find the changes both affordable and acceptable? How reform is implemented is crucial if confidence in the railways and the ticketing system is to be shored up and value for money ratings pushed up.

"How do you avoid pricing passengers off while simultaneously making it worthwhile for passengers to travel at different times? Significant peak price hikes might force many into an unpleasant choice: pay up or change job, if you can."